Re: bad rss-counter message in 3.14rc5

From: Andrew Morton
Date: Tue Mar 11 2014 - 00:57:41 EST


On Tue, 11 Mar 2014 00:51:09 -0400 Dave Jones <davej@xxxxxxxxxx> wrote:

> On Mon, Mar 10, 2014 at 09:46:12PM -0700, Andrew Morton wrote:
> > On Mon, 10 Mar 2014 20:13:40 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > > > Anyone ? I'm hitting this trace on an almost daily basis, which is a pain
> > > > while trying to reproduce a different bug..
> > >
> > > Damn, I thought we'd fixed that but it seems not. Cc's added.
> > >
> > > Guys, what stops the migration target page from coming unlocked in
> > > parallel with zap_pte_range()'s call to migration_entry_to_page()?
> >
> > page_table_lock, sort-of. At least, transitions of is_migration_entry()
> > and page_locked() happen under ptl.
> >
> > I don't see any holes in regular migration. Do you know if this is
> > reproducible with CONFIG_NUMA_BALANCING=n or CONFIG_NUMA=n?
>
> CONFIG_NUMA_BALANCING was n already btw, so I'll do a NUMA=n run.

There probably isn't much point unless trinity is using
sys_move_pages(). Is it? If so it would be interesting to disable
trinity's move_pages calls and see if it still fails.

Grasping at straws here, trying to reduce the amount of code to look at :(
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